Wrong thinking

[kevinsbro]

Can someone help me understand why when

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vector3df rot, pos;
pos.set(9.0,17.0,8.0);
rot.set(67.0,90.0,50.0);
 
pos.set(rot.rotationToDirection(pos));
rot.invert();
pos.set(rot.rotationToDirection(pos));
 

position doesn't still equal [9.0,17.0,8.0] ????

All its doing is rotating a vector and then rotating it back right?

[shadowslair]

Because rotationToDirection() returns a unit (normalized) vector? It just rotates a unit vector by the euler angles. IMO the last part of code doesn`t make much sense at all.

[smso]

I guess "rot" in your case means the orientation of the scene node and it is different from the rotation operation. If the rotation operation is done by matrix, then

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core::vector3df pos(9.0f, 17.0f, 8.0f);
printf("(%f,%f,%f)\n", pos.X, pos.Y, pos.Z);
 
core::vector3df zdir(0.0f, 0.0f, 1.0f);
core::vector3df rot(67.0f, 90.0f, 50.0f);
core::vector3df dir = rot.rotationToDirection(zdir);
// or core::vector3df dir = rot.rotationToDirection();
// since arg. defaults to zdir 
 
 
core::matrix4 mat;
mat.buildRotateFromTo(zdir, dir);
mat.transformVect(pos);
printf("(%f,%f,%f)\n", pos.X, pos.Y, pos.Z);
 
mat.buildRotateFromTo(dir, zdir);
mat.transformVect(pos);
printf("(%f,%f,%f)\n", pos.X, pos.Y, pos.Z);

Regards
smso

[kevinsbro]

Thank you so much! I still don't understand why my code didn't work though. rotationToDirection takes the vector you want to rotate as a parameter. Shouldn't my code just be rotating it and the rotating it right back?

[smso]

Don't be misled by the function name "rotationToDirection". It really means "orientationToDirection" or "getDirectionVectorFromOrientation". The argument of "rotationToDirection" is the reference direction or heading of the scene node when

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node->getRotation().equals(core::vector3df(0.0f))

Also

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core::vector3df rot(67.0f, 90.0f, 50.0f);

does not represent operations on the scene node of :
first rotating it about xaxis by 67.0f deg,
then rotating it about yaxis by 90.0f deg,
...

Regards
smso